Method of making cellular structures



April 2, 1952 R. H. ROBINSON 2,593,714

METHOD OF MAKING CELLULAR STRUCTURES Filed June 50, 1945 12 Sheets-Sheet l April 22; 1952 R. H. ROBINSON 2,593,714

METHOD OF MAKING CELLULAR STRUCTURES Filed June so, 1943 12 Sheets-Sheet 2 April 22, 1952 R. H. ROBINSON 2,593,714

METHOD OF MAKING CELLULAR STRUCTURES Filed June so, 1943 12 Sheets-Sheet s I 61 f3 53 51 l 3 W U April 1952 R. H. ROBINSON I 2,593,714

METHOD OF MAKING CELLULAR STRUCTURES Filed June 30, 1943 12 Sheets-Sheet 4 I 5 V 56 55. 1%? 3' r 4 I 1 L r2- 6 5/2 35 M i ffllmlw W April 22, 1952 R. H. ROBINSON 2,593,714

METHOD OF MAKING CEELLULAR STRUCTURES Filed June 50, 1945 12 Sheets-Sheet 5 R. H. ROBINSON METHOD OF MAKING CELLULAR STRUCTURES April 22, 1952 12 Sheets-Sheet 6 Filed June so, 1943 5 April 22, 1952 R. H. ROBINSON 2,593,714

METHOD OF MAKING CELLULAR STRUCTURES 12 Sheets-Sheet 7 Filed June 30, 1943 BEEEQQE A ril 22, 1952 R. H. ROBINSON 2,593,714

METHOD OF MAKING CELLULAR STRUCTURES Filed June 30, 1943 12 Sheets-Sheet 8 q ww/ J 1 5 159 Q 155 41 /I/ I HI 1 50 0125 April 22, 1952 R. H. ROBINSON METHOD OF MAKING CELLULAR STRUCTURES l2 Sheets-Sheet 9 Filed June 50, 1943 April 2, 1952 R. H. ROBINSON 2,593,714

METHOD OF MAKING CELLULAR STRUCTURES Filed June 30, 1943 12 Sheets-Sheet 10 55 I 52 a? I 52"" 55 G H ns a 59 fis. .wy m

a 1, 58 51 w 1 15 15 15s 53 c W l 0. m

April 1952 R. H. ROBINSON 2,593,714

METHOD OF MAKING CELLULAR STRUCTURES Filed June 30, 1943 12 Sheets-Sheet 11 April 22, 1952 R. H. ROBINSON" 1 METHOD OF MAKING CELLULAR STRUCTURES Filed June 30, 1945 12 Sheets-Sheet l2 Patented Apr. 22, 1952 UNETE STTES OFFICE METHOD F MAKING CELLULAR STRUCTURES Claims.

This invention is directed to the development for aircraft, boats, cars and general structural purposes, of light cellular structural shells, framing. and other elements formed or molded under pressure at predetermined temperatures with plastic materials and particularly those combining plastic, as a bonding agent, with wood veneers, fabrics, fibrous or metallic elements, or combinations of same, and consists of certain novel improvements and variations in the construction disclosed in my co-pending application Ser. No. 455,350, filed August 19, 1942, now abandoned, of which the instant application is a continuationin-part, as well as embodying other additional features which improve the structures as well as greatly facilitate the speed and economy of manufacture.

A further important object of the invention is to make possible the forming of these cellular structures with thin interior walls and in all manner of curved or irregular shapes and sizes not heretofore feasible with the use of interior shaping mandrels which thisinvention novelly eliminates; to furthermore and at the same time secure the same forming pressure on the interior walls of the structure in any and all positions, the same as on the exterior surfaces; and by new and novel methods for forming and pressure treatment as well as novel structural designs make possible and practicable, economical and expeditious mass production on a large scale not heretofore attained in plastic and pressure forming.

A further object is to introduce new and greatly improved methods for easily providing molds and pressure chambers on an unlimited scale and in certain instances even to eliminate in whole or part either the heretofore required molds or the pressure tank or both and to provide novel and more simple means for applying the curing fluid pressure and temperature required in plastic molding and bonding and, particularly, quickly and without injury to the interior of structures of substantial depth, a matter which has heretofore presented a dimcult problem.

A still further object is to make possibl the forming of large plastic or plastic bonded bodies and structures in multiple in one operation and, among still other important purposes, to bring about important savings in the use of critical war materials and minimize the employment of metal both in the structures themselves and likewise in the molds and pressure tanks for plasti cally forming or bonding same.

The many other objects and advantages of my invention will be better understood by reference 2 to the following specification when considered in connection with the accompanying drawings illustrating certain embodiments thereof in which:

Fig. 1 is a fragmentary perspective view of a simple form of tube for use in forming cellular structures, etc.

Fig. 2 is a fragmentary perspective view of the tube including additional reinforcements.

Fig. 3 is a fragmentary perspective view of a portion of the tube and reinforcing as in Fig. 2.

Fig. 4 is a fragmentary perspective view of the tube with modified reinforcing arrangement.

Fig. 5 is a fragmentary perspective view of the tube with further modified reinforcing arrangement.

Fig. 6 is a fragmentary plan of one form of jacket reinforcing for the tube.

Fig. 7 is a fragmentary plan of a modified form of jacket reinforcing.

Fig. 8 is a fragmentary cross section showing a group of tubes with reinforcing jacket in assembly position in form before compression.

Fig. 9 is a fragmentary cross section showing the tubes of Fig. 8 after compression in the form.

Fig. 10 is a fragmentary plan of a modified form of jacket reinforcing.

Fig. 11 is a fragmentary plan of a modified form of jacket reinforcing.

Fig. 12 is a fragmentary cross section showing a group of tubes with reinforcing jacket similar to that of Fig. 11 compressed in a form to form a corrugated shell structure.

Fig. 13 is a fragmentary side elevation of a tube encased in the jacket of Fig. 10.

Fig. 14 is an end view of a tube such as in Fig. 13 with the jacket before same is closed.

Fig. 15 is an end view of the tube of Fig. 14 after the jacket wrapping is closed about same.

Fig. 16 is a fragmentary side elevation in diagrammatic form showing how an articulated jacket of the type of Figs. 10 and 13 permits the adaption of the tube to a curved surface with greater facility, etc.

Fig. 1'7 is a fragmentary perspective view of a modified tube and reinforcement.

Fig. 18 is a fragmentary perspective view of a group of tubes of the type of Fig. 17 after compression in the form after assemblage and with an all-over shell sheathing included.

Fig. 19 is a fragmentary perspective view of a modified tube and reinforcement.

Fig. 20 is a fragmentary perspective view of a group of tubes of the type of Fig. 19 after compression and with sheathing.

Fig. 21 is a fragmentary perspective view of a modified form of tube and reinforcement.

Fig. 22 is a fragmentary perspective view of a group of tubes of the type of Fig. 21 after compression and with sheathing.

Fig. 23 is a fragmentary perspective view of a modified tube and reinforcing.

Fig. 24 is a fragmentary perspective view of a group of tubes of the type of Fig. 23 after compression and with sheathing.

Fig. 25 is a fragmentary perspective view of a modified tube with reinforcing.

Fig. 26 is a fragmentary perspective view of a modified tube and reinforcing.

Fig. 27 is a fragmentary perspective view of plastic bonded and reinforced veneer ply" em tails of the manifold connections with the plastic tubes assembled in the pressure form as in Fig. 36.

Fig. 47 is a fragmentary side elevation of the manifold injection or outlet connections, etc., of Fig. 36.

Fig. 48 is a fragmentary perspective view of a reinforced plastically formed cellular shell formed as in Fig. 36, etc.

Fig. 49 is a fragmentary plan of tubes, etc., in assembled position in the form producing cellular truss frames, etc., after the manner of Fig. 36, etc.

Fig. 50 is a fragmentary cross section of the form of Fig. 49 with the closure lids in place and the tubes, etc., in compression.

ployed in the tube reinforcing, sheathing, etc.

Fig. 28 is a fragmentary perspective view of a modified form of plastic bonded and reinforced veneer ply likewise employed.

Fig. 29 is a fragmentary perspective view of a modified form of tube reinforcing.

Fig. 30 is a fragmentary perspective view of a group of tubes of the type of Fig. 29 after compression.

Fig. 31 is a fragmentary perspective view of a. group of tubes and reinforcing in modified form in assembled position before compression, etc.

Fig. 32 is a fragmentary perspective view of the assembled tubes of Fig. 31 after compression, etc.

Fig. 33 is a fragmentary perspective view of a modified form of tube (with broken away wall.)

Fig. 34 is a fragmentary perspective view of a tube and reinforcements laid in a containing and reinforcing envelope.

Fig. 35 is a fragmentary perspective view of a group of tube and envelope assemblagessirnilar to Fig. 34 after compression in assembled position.

Fig. 36 is a fragmentary plan of tubes, etc., in

assembled position in the form.

Fig. 37 is a fragmentary cross section of the tubes in the form before compression.

Fig. 38 is a fragmentary cross section similar to Fig. 37 showing same after the tubes are compressed in the form with the closure lids in place.

Fig. 39 is a fragmentary cross section of tubes compressed in a modified form, etc.

Fig. 40 is a fragmentary perspective view of a modified type of form, filled with tubes and corn pressed under a cellular membrane closure coverg' Fig. 41 is a grammatic form showing a cellular shell formed by interior fluid pressure inthe assembled tubes and shaped for tongue and grooved joining.

Fig. 42 is a similar fragmentary cross section of the cellular shell and including integrated exterior sheathings and additional web members inserted between the tubes and their -reinforcements of whatever type employed.

fragmentary cross section of die- Fig. ,51,is a fragmentary cross section of the form of Fig. 49 of a modified type distinct from that of Fig. 50 in having a sheathing extending across the upper side of the truss and a compression bag (or bags) included in the form for completing the plastic pressure treatment of same.

Fig. 52 is a fragmentary side elevation of a modified form of cellular truss plastically formed and integrated after the manner of Figs. 49 and 50.

Fig. 53 is an end view of a truss of the type of Fig. 52 formed with a plurality of tube tiers laid in the form.

Fig. 54 is a cross section of a truss formed by connecting and joining together two veneer or ply sheathed trusses individually formed as in Fig. 51 and of the design of Fig. 52.

Fig. 55 is a fragmentary plan showing a modified form of the cellular truss framing for spars, ribs, etc., the tubes, etc., being placed in the forms similarly to Figs. 49, etc.

Fig. 56 is a fragmentary plan of the tube wall (in the fiat before jointing) where it is desired to use a tube of changing or varying diameter in a structure such as that of Fig. 55 instead of the tubes of constant diameter there indicated.

Fig. 57 is a fragmentary side elevation of the tube formed on the plan lay-out of Fig. 56 and joint seamed so providing tapering cord members, etc., for the truss of Fig. 55 or other structures.

Fig. 58 is a plan of plastic tube framing for a wing, formed after the manner of Figs. 49, etc., and with the use of a single continuous tube.

Fig. 59 is a fragmentary cross section of a frame of the type of Fig. 58 on line 59--59, with the addition of sheathing across the upper face after the manner of Fig. 51.

Fig. 60 is an end view showing a frame of the type of Fig. 58 in three tier construction.

Fig. 61 is a plan of plastic tube framing for a double wing, or other structural framing.

Fig. 62 is a fragmentary cross section of a plastic tube formed girder, spar or shell structure and trench form "for forming same.

Fig. 63 is a fragmentary perspective showing a cellular spar or other frame of tapering depth formed with constant diameter tubes and having truss reinforcements, etc.

Fig. 64 is a fragmentary cross section of a sheathed and web reinforced cellular frame or shell and the form for compressing same.

Fig. 65 is a cross section of a modified form of frame or shell of the type of Fig. 64.

Fig. 66 is a fragmentary cross section of modified cellular shell or frame similar to that of 5 I Fig. "68'is'a fragmentary cross section of a laminated shell plastica-lly formed with a tubular beam member. Y

Fig. 69 is a fragmentary cross section of a modified form of shell and beam member similar to that of Fig. 68.

Fig. 70 is a fragmentary cross section of another modified form of shell and beam member similar to Fig. 68.

Fig. 71 is an end view of a modified form of tube for forming cellular shells, etc.

Fig. 72 is a fragmentary side elevation of tubes of the type of Fig. 71.

' Fig. 73 is a fragmentary cross sectional per spective view of a modified form of tube.

Fig. 74 is a diagrammatic fragmentary cross section of the laminated construction of a tube wall of the type of Figs. 71 and 72.

Fig. 75 is a diagrammatic fragmentary cross section of modified tube Wall constructions similar to Fig. 74.

Fig. 76 is a diagrammatic fragmentary longitudinal cross section showing the plastic joining of the walls of assembled adjacent tubes of the type of Figs. 71 and 74 in the forming of a cellular shell or frame.

Fig. 77 is a fragmentary cross sectional view of a modified form of tube or tubular structure and container for pressure forming same.

Fig. 78 is a plan showing the tubular formation of a mat coiled type suitable for airplane wings and other cellular shells.

Fig. 78a is a fragmentary plan showing alternate offset coil terminal.

Fig. 79 is a front elevation of the shell shown in Fig. 78.

Fig. 80 is a front elevation of a modified form of shell formed similarly to that of Figs. 78 and 79 and indicating possible application to a fuselage.

Fig. 81 is a diagrammatic transverse cross section of a wing or other shell similar to that of Fig. 78, etc.

Fig. 82 is a diagrammatic transverse cross section of a modified form of curved Wing or other shell formed after the manner of Fig. 78,'etc.'

Fig. 83 is a diagrammatic transverse cross section of a modified form of Wing formed after the manner of Fig. 82 but with varying thickness of cellular shell to provide a predetermined aerodynamic shape.

Fig. 84 is a fragmentary front elevation of cellular wing shells similar to that of Fig. 80 and joined with a fuselage. I

Fig. 85 is a diagrammatic transverse cross section of a wing formed after the manner of Figs. 8% and. 83, with the additional leading edge and trailing edge closing members added thereto.

Fig. 86 is a fragmentary plan of a veneer band assemblage for providing a reinforcing wrapping of tubes for forming the cellular structures.

Fig. 87 is a fragmentary side elevation of a tube with the jacket wrapping of Fig. 86..

Fig. 88 is a cross section of the wrapped tube of'Fig. 87.

Fig. 89 is a fragmentary longitudinal side elevation showing a modified way of applying the wrapping band of Fig. 86 on the tube.

Fig. 90 is a diagrammatic fragmentary front elevation of a wing shell formed similarly to that of Fig. 84 but embracing wing nacelle shells as well as fuselage.

Fig. 91 is a fragmentary side elevation of a coil formed fuselage with wings and nacelles similar to Fig. 90.

Fig. 92 is a fragmentary longitudinal cross sec- .tionshowi'ng the fuselage and wing shell joinings' in a fuselage of the type of Fig. 91 but made in two joined sections.

Fig. 93 is a fragmentary cross section of the tubular Wall'shell of the type of Fig. 91 in relation to thelattice shell wrappings with and without sheathing.

Fig. 94 is a fragmentary cross section of th shell. similar to Fig. 93 butincluding an exterior and also an interior sheathing over the lattice.

Fig. 95 is a fragmentary cross section of the shell similar to Fig. 94 but in two tier construction and with an intermediate lattice and sheathing wrapping between tiers as Well as on the two outer surfaces.

Fig. .96 is a fragmentary cross section of the shell. similar to Fig. 95 but Without intermediate lattice and sheathing wrappings between the two tube'tiers and having a tubular lattice. covering.

Fig. .97 is a fragmentary cross section of a tube formed shell formed in combination with a tube formed beam member, with the shell tubes extending transversely of the beam tube.

Fig. 98 is a fragmentary cross section of a tube formed shell, etc., similar to Fig. 97 but with the shell tube extending parallel with the tube beam.

Fig. 99iis a fragmentary longitudinal cross section of a tube formed shell with graduated or stepped up sheathing reinforcing.

Fig. 99a is a fragmentary cross section of Fig. 99 on line 99a-99a.

Fig. 100 is a fragmentary cross section of a two tier shell similar to that of Fig. 96 but with staggered tube cross joints and meshed wire in lieu of the latticed strip or tube wrappings and without exterior sheathing.

Fig. 101 is a fragmentary cross section of a shell similar to Fig. 100 but with tube joints aligned instead of staggered and with wire ties between the tubes andanchoring the outer wire mesh wrappings together on predetermined spacings and including exterior sheathing's over the wire mesh wrappings.

Fig; 102 is a fragmentary cross section of a two tier shell with veneer sheathing in'combination with an outer wall of metal and showing reinforcing webs between tubes and exterior means of connections.

Fig. 103 is a cross section of a coil formed fuselage and pressure chamber for same.

Fig. 104 is a fragmentary side elevation of the fuselage and longitudinal cross section of the .pressure chamber of Fig. 103.

Fig. 105 is a fragmentary side elevation of a fuselage showing certain types of tube coiling and forming.

the tubular dowel connections used in Fig. 108.

Fig. is a fragmentary perspective of a tubular body with shell of longitudinally disposed tubing and with body framing, etc.

Fig. 111 is. a cross section of a tubular body of the type of Fig. 110 but with transverse coiled tubing and showing cross section of molding pressure chamber for forming. I

Fig. 112 is a fragmentary perspective of framing members employed in Figs. 110,. 111 and the like.

Fig. 113 is a cross sectionof a modified form of .tubular body with the cellular shell.

Fig. 114 is a cross section of a coiled form of fuselage and forming pressure chamber and modified means of molding.

Fig. 115 is a side elevation of a coiled form of fuselage and modified pressure chamber and means of molding.

Fig. 116 is a cross section of a coiled formed fuselage of the type of Figs. 105 and 106, with framing and alternate tube formed interior framing and pressure chamber and modified means of molding.

Fig. 117 is a fragmentary cross section showing the longitudinal plates and separator spacers and tube beam .of .the fuselage shell of Fig. 116.

Fig. 118 is a fragmentary cross section of the frame and beam of Fig. 117 on the line 1 18-4 18.

Fig. 119 is a fragmentary cross section similar to Fig. 118 but with longitudinal tube formed interior frames omitted and showing external connections for bulkhead, etc.

Fig. 120 is a cross section of a portion of a fuselage or tubular body, made in separate sections, and the pressure chamber and means of molding.

Fig. 121 is an end view of an assembled fuselage of the type of Fig. 120.

Fig. 122 is a fragmentary side elevation of the fuselage of Fig. 121.

Fig. 123 is a fragmentary side elevation of a modified form of side section truss elements shown in Fig. 122.

Fig. 124 is an end view of the truss form of Fig.

Fig. 125 is an end elevation of tube reel carrier laying tubes in'trench form.

Fig. 126 is a cross section of a pressure chamber showing modified bag method of forming plastic molded elements.

Fig. 127 is a fragmentary side elevation of plastic tube formed propeller blades.

Fig. 128 is a cross section of the tube formed propeller blade in molding form.

Fig. 129 is a fragmentary diagrammatic longitudinal cross section showing wall features of the tube formed propeller blade.

Fig. 130 is a cross section of a tube formed wing in forming and pressure chamber.

Fig. 131 is a fragmentary plan showing form and manner of forming wings of the type of Fig. 131 in continuous multiples.

Fig. 132 is a cross section of a modified form of tube formed wing.

Fig. 133 is a fragmentary perspective showing tube and truss insert construction as in Fig. 132.

Fig. 134 is a plan showing tube formed wing construction similar to Fig. 132.

Fig. 135 is a fragmentary perspective of a modified form of tube formed wing.

Fig. 136 is an end elevation of wing of the type of Fig. 135.

Fig. 137 is a fragmentary cross section showing method of forming two tube coiled wings, edge to edge in a continuous coiling.

Fig. 138 is a fragmentary cross section showing means for more readily coiling tubing for wings, etc., around the trailing edge or an abrupt turn of similar nature.

Fig. 139 is a fragmentary perspective showing a modified form of tube formed wing with diag- Fig. 142 is a fragmentary plan of the tube end construction in Fig. 141.

Fig. 143 is a fragmentary perspective of another modified form of wing.

Fig. 144 is an end elevation of a modified form of wing.

Fig. 145 is a fragmentary side elevation of the central tubular spar of Fig. 144 on line I45l45.

Fig. 146 is an end elevation of a modified form of wing.

Fig. 147 is an end elevation showing method of coiling wing of the type of Fig. 146 in vertical position.

Fig. 148 is a fragmentary cross section of a tube formed shell of the type of Fig. 146 but of two tier tube construction.

Fig. 149 is a fragmentary cross section of a tube formed shell of the type of Fig. 146 in single tier tube construction.

Fig. 150 is a cross section of a modified form of cellular shelled wing made in sections and then joined.

Fig. 151 is a plan of another modified form of wing.

Fig. 152 is an end View of the wing of Fig. 151 in position of assembling and molding.

Fig. 153 is a fragmentary cross section taken through the wing of Fig. 151 on line |53I 53.

Fig. 154 is a fragmentary cross section of a modified form of the construction shown in Fig. 153.

Fig. 155 is a cross section showing another modified form of tube coiled fuselage or tubular body and means of pressure molding same.

Fig. 156 is a fragmentary longitudinal side elevation showing the joining of preformed cellular shelled sections for fueslage or tubular bodies.

Fig. 157 is a fragmentary perspective of a modified form of tubular body with cellular shell.

Fig. 158 is a fragmentary perspective of a modified form of cellular girder, spar or frame member.

Fig. 159 is a fragmentary cross section show ing a form of metal framing and joining for cellular formed shell sections, etc.

Fig. 160 is a fragmentary perspective of another modified form of cellular girder, spar or frame member.

Fig. 161 is a fragmentary cross section showing anchor or expansion bolt connection for sheathing, etc., to a cellular spar or girder similar to that of Fig. 160.

Fig. 162 is a fragmentary cross section showing nailing connection for plywood sheathing, etc., to a cellular spar or girder shown in Fig. 169.

Fig. 163 is a fragmentary end elevation of a modified form of wire mesh reinforced tube formed girder, spar or frame member and indicating its joining with a tube formed shell extending transversely thereof.

Fig. 164 is a fragmentary end elevation of another modified form of Wire mesh reinforced tube formed girder, spar or frame member and indicating its joining with a tube formed shell having tubes extending longitudinally therewith.

Fig. 165 is a fragmentary end View of a tube formed shell in combination with ribbed expanded metal.

Fig. 166 is a fragmentary perspective of a modified form of tube formed truss or spar.

Fig. 167 is a fragmentary perspective of a plastic tube formed ladder or frame member.

Fig. 168 is an end view of a plastic tube formed beam with reinforcements.

Fig. 169 is an end view of a modified plastic tube formed beam with indicated joinings with preformed cellular tube formed panel shells.

Fig. 170 is a fragmentary perspective of a plastic tube formed frame for tennis or other rackets.

Fig. 171 is a fragmentary persepctive of a plastic tube reinforced or formed tube with interior reinforcing walls.

Referring in detail to the drawings, Fig. i represents one of the various forms of tubes which I novelly employ in forming my various cellular plastic, veneer and other compound structures Where any suitable materials are integrally united and bonded together by any of the various so-called plastics, or the like, in the curing and hardening of the adhesive material so employed. The hollow or tubular elements I are susceptible to a wide variation in construction. My chief aim is to provide these in most economical forms suitable to mass production and to procure a maximum of strength and durability. In this intance thetube l is formed with a wall 2 of fabric of good tensile strength which is properly coated or impregnated with water-proofiing or fluid-proofing material 3 which will resist the pressure of water, air, steam, or whatever fluid it is preferred to use in subsequently inflating the tube with interior pressure. This fluid-tight wall 3 may be the innermost one, as shown, but it may also be otherwise located as in the case of covering same with a further inner lining of protective paper or cellophane or other film (not shown) which may be found helpful in forming or ouring the fluid-tight wall or coating, or for structural or other reasons. The fluid-proof material may in normal times be of natural or synthetic rubber but under present war conditions and the necessity of avoiding the use of critical materials which is also one of the purposes of this invention, I prefer to use the commercially produced material known under the trade name of Fairprene, either as a coating or as a sheet or film which forms in itself a strong pliable and fluid-proof wall with numerous other desirable qualities. Another suitable commercial material is known as Safiex. This is a modifled polyvinyl butyral prepared for fluid-proofing fabrics and the like which is thermosetting, curing at 2620 degrees F., so as to produce a tought pliable coating, with many excellent qualities. if the. conditions to be met with permit the use of thermoplastic material rather than thermo setting, another possible material of such fluidtight, pliable and elastic walls can be formed is ethyl rubber produced from ethyl cellulose. It will be understood however that I no not limit my construction to these or to any one specific material and many coacting 01' wall or film of suitable material which best meets the requirements of the particular situation may be employed or a variety or combination of different materials may be used for this purpose in the same structure. It will also be understood that while generally the fluid-proofing 3 is preferably coated on the wall 2 (which can be either fabric, paper, tensile film, or other adaptable material), it may be made as a separate wall in itself and embodied or inserted in the tube and in any desired way. Where only air pressure is employed in the subsequent pressure treatment for hardening the plastic or adhesive components, it is not necessary to employ more expensive waterproof or steam-proof wall or coating materials and where water pressure is employed but without special heat requirements inexpen- ,sive coating substitutes can be used meeting;

lining serves a double purpose both as the fluid-.

tight member making the interior water or steam pressure treatment possible and also, thereafter, in the completed structure a permanent means for keeping the atmospheric or other moisture from reaching the wood members.in-'

teriorly, and so minimizing deterioration and warping tendencies, etc. It should also be understood that the wall 2 in the form of fabric can be entirely omitted and the water-proof or fluidtight wall 3 used merely with intervening plastic and an outer wall of veneer or other fibrous or tensile wrappings or jackets. It will also be understood that the water-tight, air-tight or fluidtight lining or wall 3 included in the tube may serve as only a temporary protective element permitting the use of inexpensive protective coating or wall materials which are only required to remain water-proof, air-tight or other fluid-tight, as the case may be, for the pressure hardening period which may be as short. asten minutes with some plastic materials.

The base material 2 forming the tube, if of fabric, can be a seamless braided tube, or if a seamed tube, as indicated in this particular Fig. 1, the weave of the material is preferably 31-! though not necessarily disposed diagonally or on the bias. In all these cases the tube so formed with its weave diagonally disposed will so better conform to changing curves when laid in forms requiring curved structures. The material so diagonally disposed also provides additional strength for resisting torsion and shear in the finished structure. If the seamed tube form is used the flat material may be joined by any suit.- able lapped or locked joint 4 with the adhesive material disposed to set within the joint which is preferably stitched to secure the best strength.

One of the features of my invention is to do away in whole or part with the necessity of mandrels in the preliminary forming of the tube.

while my novelly dispensing with finishing mandrels in the final formingof the cellular structure, as hitherto found necessary, makes possible the forming in mass production, as will be later brought out, cellular structures of practically unlimited length and size and of curved and irregular shapes not feasible with 1 interior finishing mandrels. As my tubes are not single or of laminated or multiple construction and with further fluid-proofing if desirable, between layers and, in such case, seamed joints may be staggered to secure maximum pressure resistance where such is needed' 'In its simpler form as shown in Fig. 1, however, I use a single wall for 3 for minimum cost of production. In

consideration of cost, etc., I also form the wall 3, when desired, of suitable paper in single or multiple ply and similarly, for some cases, of cardboard.

The fluid-proofed wall 2 is provided as noted with an exterior coating or an impregnation of plastic material P in any preferred form and becomes, it should be particularly noted, a structural part and reinforcement of the finished pressure hardened structure. The service required, cost, etc., will determine the selection of the plastic and either a thermosetting or thermoplastic adhesive may be used and of the type most suited to the case in hand. Also in lieu of a coating, impregnation or the like, this plastic wall may be provided as an independent plastic wall, film or bonding sheet, or the plastic bonding material may instead be applied to adjoining members which will be brought to bear on the wall 2 when the subsequent pressure process i applied. For aircraft, boat structures, etc., I prefer to use, under the present state of the plastic art, the thermosetting type of plastic, particularly the phenol and urea types of synthetic resin which particularly recommend themselves for permanent structural superiority, which bond well with wood veneers and other filler or reinforcing material employed in my structures as well as being generally more economical. Where thermoplastic material is permissible or desired, cellulose acetate, or polyvinyl butyral or other accepted products can be used as the plastic bonding and strengthening agent. Any other suitable adhesive may be employed in lieu of any of these plastics as the bonding agent and different ones may be used in the same structure and at one and the same time.

The laminated walls of the tube I may have added any desired number of additional layers of preferred and varied material in wound, wrapped or other form, the same being combined in one form or another with interposing plastic or adhesive and with an outer wall of plastic or adhesive, applied in any of the various ways common to the art. The tubes l are made of any length but preferably of long continuous lengths and, as already noted, it is not necessary to. make the same on a forming mandrel as they are not preformed tubes which, formed solely of plasticized veneer, have been made on forming mandrels and combined on finishing mandrels in a very limited and impractical way.

My tubes, instead, doing away with final forming mandrels, are of a distinctly different nature and are finally formed, shaped and united by interior fluid pressure in all manner of shapes, lengths and sizes, without'mandrels and their narrow limitations and great expense.

The tubes l are in most instances preferably combined with outer layers of reinforcing ma-- terials of good tensile strength associated and bonded with plastic. At the present time, one of the most preferred of these is wood veneer or plywood, although I also use other fibrous materials, fabrics, metals, etc., and often combine various of these in combination with the tubes I and the integrating adhesives. These reinforcing materials and fillers may either jacket the individual tubes or blanket or combine with assembled groups of same and I combine the various elements in many novel ways which will be subsequently indicated in part.

In Fig. 2 is shown one of these jacket arrangements. Instead of covering the tube 1 solidly with wood veneer or other tensile material, I novelly distribute same in depth rather than in area by forming open and lattice work jackets. The size of the jacket is preferably smaller than in Fig. 2. In the lower section of same, the tube is provided with longitudinal strips 6 and trans-'- verse strips I, while in the upper section of same these are supplemented by diagonal strips 8 and 9 for resisting shear and torsion.

In Fig. 3 is shown in detail the construction of the tube 1 in relation to the reinforcing strips of the jacketing members such as the longitudinal strips 6 of Fig. 2. The construction, materials and arrangement employed in these structural jackets and wrappings for the tubes can be greatly varied and these become eventually an integral part of the tube to which they are loosely applied for assemblage purposes. In this instance the reinforcement E5 is shown in laminated ply although it may likewise be formed of single veneers or other tensile materials, including metal or combinations of same. In this figure a three ply veneer-with plastic or adhesive interplayers or coatings P is indicated and with. the face members 6a and 6b having their grain extending longitudinally of the strips (and in,

this position the tube as well) while the core member 6c extends crosswise in a typical balanced plywood construction, the several lamina tions of the plywood 8 and the outer surfaces of the tube Wall 2 being combined at all points of contact with the thin layer of plastic P as indicated. A further wall or sheathing 5 of veneer, fabric or any desired material is shown plastically united to the plastic covered outer surface of the tube wall and any number of such laminations may be combined with these tubes as complete surrounding casings or as surface sheets of the finished cellular shell structure to form which these tubes are assembled and plastically united under pressure as will be subsequently brought out. This outer sheathing wall is also preferably covered with a finished coat of the plastic material (P) which can be either impregnated or coated or otherwise supplied and particularly by laying on sheets of thin plastic or plastic coated tissue or film material. In lieu of veneers for the strips 6, l, 8, 9 and the like, thin flexible strips of metal may be used as already noted. These can be alum inum or magnesium or their alloys, for example, and so form the laminations 6a, 6b and 60; or 60 may remain of wood veneer or again both 6b and 60 may be veneer forming an integrated wood backing for the metal member 6a. other desired combinations may be made and with other materials. Particularly desirable is the use of heat treated high tensile strength steel alloys such as stainless or chromium nickel steel, trade named 18-8, and the like. These can be metallically or molecularly joined by welding or brazing Where wanted and particularly in the case of chrome steel alloy by spot welding to which it is especially suited as well as to heat treating for developing exceptional tensile strength and desirable physical properties. This welded joining can be so done where the ribs.

as G and 1 and 8 and 9 contact each other at points of crossing. If preferred, however, the welding can be omitted and plastic adhesives now especially and successfully developed for bonding metal surfaces can be used as coatings Any 13 between the contacting surfaces as P in Fig. 3. The same may be done with the outer sheathing or sheeting 5 which may be similarly of sheet metal plastic'ally bonded to the tube structures or wood backing laminations, etc.

It should be further noted as an important feature of my invention that not only light and flexible metal bands may be used for the wrapping or jacket tube reinforcement members such as 6, I, 8, 9, and the like, but that similarly these may be supplied in the form of metal wires preferably light and flexible and or high tensile strength. These can be interwoven r joined by welding or other means at the contact points. Bands of such woven or joined wires may also be used in band or strip formation the same as the bands of Figs. 2, 3, 4, 5, and subsequent figures. The flexible tube walls on inflation or expansion of the plastic tube, press in between the wires of the mesh the same as with the equivalent strip elements so as to partially embrace or form flush exterior surfaces with same in the final pressure integrating. A further unique feature of my invention in relation to the employment of the metal strips or wire elements as reinforcing parts of my plastic tubes and cellular structures, is to provide these in metals which acquire great tensile strength and other advantageous physical properties such as fatique resistance, etc, through heat treatment in connection with aging over a period of time rather than immediately through the quenching bath. Such metals of particular note are chrome steel alloy, as 18-8, and also Duralumin. In such cases I complete my assemblage, shaping and pressure treatment for the cellular structure to be formed subsequent to the heat treating of these metal elements but prior to their necessary aging and as a result they acquire their final flexed and bent shapes and position in the structure before their aging and stiifening and their final set, so to speak, in their permanent positions and shapes as intended.

In Fig. 4, in the lower section, the tube is embraced with diagonal strips only, the strips 8 and 9 in this case may be interwoven in the winding or with one winding merely wound on top of the opposite lattice member. In the upper section of Fig. 4. only a single lattice winding is relied on, this simple arrangement being made more feasible owing to the fact that when a plurality of such tubes are combined side by side, the shearing stresses are met in opposite directions due to the fact that the diagonal windings of like adjacent tubes placed in similar manner dispose themselves as opposite diagonals on their opposing side walls which become ultimately united. In Fig. is shown'arrangements of windings for covering tubes solidly with the veneer, or other tensile material. In the lower section the winding 9 is lapped on itself as noted so that the tube is not only solidly encased but a double formed rib 9a is formed by the lappage, spiralling around the tube. In the upper sections the opposite diagonal windings are shown with abutting edges and forming an inner and a superimposed outer wall. In this case, also, the strips 8 and 9 may be similarly lapped as in the. lower section, thus producing the double formedrib as 9a in opposite directions. If preferred, the strips 8 and 9 in the first instance same on the tubes 1. On the longitudinal strips.

6 are quickly attached cross diagonal strips 8 and 9, the same being preferably pinned, III, as noted, to the longitudinals 6 so as to permit pivoting action and movement of the diagonals when the wrapped tubes are adapted to curves. The lattice jackets so formed are wrapped about the tubes l before or as these tubes are later coiled or laid on or in their form assemblages, the longitudinals 6 being normally laid on the short side of a curve where one-way curving surfaces are involved or coiling employed. Otherwise or in the case of compound curves requiring it, the longitudinals 6 may be cross cut as at H to better permit curve adaptation and, if desired, lap strips may then be added over the joints H. Also abutting sections of jackets where they are not in continuous lengths may be similarly lap joined. When these lattice jackets are bent around the tubes 1, they are tied, clipped or otherwise suitably held or joined along the longitudinals S which can either lap or abut each other as desired. Where a solid veneer or sheet covering is permissible or wanted a similar jacket structure as indicated in Fig. 7 may be employed. In this arrangement I combine the shear strengthening strips 8 and 9 with a veneer, plywood, or other tensile sheet covering 52, the strips being pinned to same preferably at H] or in any other way found desirable.

In Fig. 8 is indicated the manner in which tubes 1 of the type of Fig. 6, with the lattice jackets tied about same and the tube walls expanded or extended within same, are laid within forming platens l3 and It indicated in dotted lines. When the platens are brought together as indicated in Fig. 9 and my interior fluid presplastic tubes I for the final curing or polymeriza tion of the plastic or adhesive bonding agent finally shaped and formed in their compressed forms as noted and integrally united to form a plastically hardened and integral cellular structure, and one of great strength and lightness.

In Fig. 10 is shown a novel method I have of forming the tube jackets in veneer, etc, in a unique form which serves a threefold purpose at one and the same time, i. e., producing an articulated structure particularly adapted to con,- forming to curves, producing internal and oppo=- sitely crossing double walled lapped band construction and distributing veneer grain structure in opposite and diagonal directions for particular resistance to shear and torsion. Strips of veneer l5 and [6 are pinned (ill) in lapped relation on a longitudinal holding and reinforcing strip 6 and. superimposed one on the other to form a double walled jacket with the veneer grain of the two walls running in opposite and diagonal directions as indicated. In Fig. 11 is shown a three ply veneer jacket of balanced construction with the grain of the faces I? and I8 running longitudinally in relation to the tube l and the core l9 grain extending crosswise. The reverse arrangement may similarly be used. This construction may be employed when a solid veneer or plywood wall is desired around the inner tubes when the plastic tubes are pressed. Where it is to be adapted to curves it also may be articulated by cutting the plied veneers in short lengths and lapping the ends so as to permit movement in adaptation to curves, after the veneer jacket has been bent around the tube walls after the manner of Fig. 12. In Fig. 12 the jacketed tubes are formed and united between the platens l3 and 14 after the manner of Fig. 9. Where it is desired to have a corrugated surface providing such additional strength the forms or platens as shown in Fig. 12 are correspondingly shaped as noted producing such a finished plastic cellular structure.

In Figs. 13, 14 and 15 is indicated the manner in which the jacketed structure of Fig. 13 is completed ready for pressing. The veneers l5 and IE are bent around and their edges held together by the tapes 20 or other suitable or customary means so as to hold same temporarily in place about the tubes l until same are placed and held in the pressing forms, after the manner of Figs. 9- and 12. Fig. 16 indicates diagrammatically how this articulated tube may be conformed to a convex curve as the lapped veneers free to move on their outer edge, slip over one another to conform to a greater perimeter.

Fig. 17 shows a plastic tube l which has pockets, sleeves or containers 2|, attached to the tube walls. These are formed of any suitable fabricv or other reinforcing material 23 in combination with plastic by coating, impregnation or the like, attached to the tube wall. 2 at desired points for stress reinforcement, in this case the top and bottom sides of the tube, by stitching 24a, cementing or other suitable anchoring along its extending edges 24. Where the tube wall is formed from flat sheet material rather than seamless (either can be used), this tube in this instance being shown assuch with a stitched and locked joint 4, the containers 2i may be attached to the sheet material in the flat if desired to simplify the procedure prior to the forming and sealing of the joint 4. The containers are filled with tensile reinforcing material 22, such as any fibrous material including wood excelsior, vegetable or synthetic fibres,

laminated material as veneers, light metal strips,

etc., or a combination of same and these are properly combined with plastic so as to unite as a structural unit in the final pressure treatment. In Fig. 18 is indicated an assembled plurality of these tubes after such treatment, the containers 2| having been so located in the first instance as to now form a strong and continuous reinforced hardened integral top and bottom wall of high compression and tensile strength which, in combination with the web members formed by the plastic union of the adjacent side walls of the flattened tubes I, create a box girder or I girder or beam forms in which the web members,

as well as the flanges or top and bottom shells, have the reinforced wall.

In Fig. 21 is shown in the lower section, small containers 21, containing small rope-likereinforcements 22 located at strategic stress points so that when pressed as in Fig. 22, they form beam-like structures with these rope-like reinforcementsforming strong plastic flanges for the web members. The fabricor sheet material 23 for the containers may extend entirely around the tube as indicated in the lower portion of Fig. 21, to form an additional reinforced plastic wall lamination, or it may be simply in strips covering each rope with extending edges 24 anchored to the tube as indicated in two of the containers in the upper portion of the figure and the same as in Figs. 17 and 19. The ropelike reinforcements themselves may be fibres in twisted rope formation as indicated in the lower portion of the figure or may be laid in without twist. In the upper portion of the figure the untwisted fibres as indicated in the central rib and an alternate construction where the sheet walls 24 are omitted and instead merely anchor straps, tape or equivalent holding means 25, anchor the fibre bundles at suitably spaced apart points. The fibre bundles or ropes and the asso ciated members are in all instances properly treated or associated with plastic prior to the final pressure treatment of the assembled struc-- tures. In Fig. 23 a modified form of the rope reinforcement similar to Fig. 21 is indicated. In this case the ropes or fibre bundles 22 are located interiorly instead of externally of the tube producing when pressed a structure similar but slightly different from that of Fig. 22 as indicated in Fig. 24. In this construction the container strips or sheets 23 can be omitted and to that of Fig. 19 with the exception that in this.

instance the containers 2| hold laminated material 26, loose or united, as veneers, plywood, metal bands, etc., or a combination of same in lieu of loose fibrous material and in combination with the necessary plastic binder. The laminations may be used in all the containers as indiwhen the tubes are assembled and pressed,-

structures similar to those of Figs. 18 and 20, etc., are secured.

In Fig. 2''! is shown a novel and strong form of plastic bonded laminated structure-for either strips or sheets and suitable for use as strips for the members 8, 1, 8, 9, 26, etc., as well as complete jacket wrappers for my plastic tube structures and likewise for plied sheathing or stressed skins, 5, etc., for my cellular assemblages. In this I employ one of my novel bonding sheets consisting of plastic coated or impregnated tissue or film 27, on the opposite surfaces of which are embedded tensile fibre elements 28, preferably disposed in opposite diagonal directions, as noted. In some instances, however, it will be found pref erable to position the fibres on both sides of the carrier film 21 in the same direction or to omit them entirely from one side and these and other variations I make as best fit the particular situation which is also affected by the number of ply laminations to be combined. This novel plastic bonding film is placed between the veneers 29 and 32 which in forming jacket strips such 

